Constructions and advances of animal models of Pseudomonas aeruginosa infection / 中华预防医学杂志

Pseudomonas aeruginosa (P. aeruginosa) is an opportunistic pathogenic bacterium with complex pathogenesis and drug resistance mechanisms. It has high morbidity and mortality and can cause acute and chronic infections in immunocompromised individuals, with lung infections, wound infections, and bloodstream infections being the most common. The animal infection model of P. aeruginosa is of great value for in-depth research on the pathogenicity, drug resistance, and therapeutic measures of P. aeruginosa by simulating the pathways of human bacterial infections. This article firstly summarizes the selection, anesthesia, and disposal of experimental animals in the construction of animal models of P. aeruginosa infection, and then reviews the methods of construction, model evaluation, and applications of animal models of P. aeruginosa pulmonary infection, wound infection, and bloodstream infection, in order to provide a reference for scientific research related to P. aeruginosa infectious diseases.

Pseudomonas aeruginosa associated pulmonary infections and in vitro amplification virulent rhamnolipid (rhlR) gene / Infecções pulmonares associadas a Pseudomonas aeruginosa e gene ramnolipídeo virulento (rhlR) da amplificação in vitro

Background: Pseudomonas aeruginosa is a common opportunistic pathogenic bacterium with the ability to develop a strong communication pathway by quorum sensing system and different virulent factors. Among the various important secretions of P. aeruginosa rhamnolipid is important biological detergent, believed to be involved in the development of the biofilm and intercellular communication. It readily dissolves the lung surfactants that are then easily catalyzed by the phospholipases and in this way is involved in the acute pulmonary infection. Objective: research work was designed to investigate virulence and gene associated with virulence in P. aeruginosa responsible for pulmonary infections. Methods: In current study polymerase chain reaction (PCR) was used for the detection of the rhlR (rhamnolipid encoding) gene of isolated strains. A number of assays were performed that ensured its virulent behavior. Disc diffusion method was used to check its antibiotic resistance. Isolated strains were resistant to a number of antibiotics applied. Result: It was found that males are more prone to respiratory infections as compared to females. Male members with age of 44-58 and 59-73 are at a higher risk, while females with age of 44-58 are also at a risk of pulmonary infections. Antibiotic resistance was observed by measuringzone of inhibition in strains GCU-SG-M4, GCU-SG-M3, GCU-SG-M5, GCU-SG-M2, GCU-SG-M1 and GCU-SG-M6. GCU-SG-M2 was resistant to fluconazole (FLU), clarithromycin (CLR), cefixime (CFM) and Penicillin (P10). No zone of inhibition was observed. But it showed unusual diffused zone around the Ak and MEM antibiotic discs. rhl R gene and 16s rRNA gene were characterized and analyzed. Conclusion: Findings from current study would help[...].

Antecedentes: Pseudomonas aeruginosa é uma bactéria patogênica oportunista comum, com a capacidade de desenvolver uma forte via de comunicação pelo sistema de detecção de quorum e diferentes fatores virulentos. Entre as várias secreções importantes de P. aeruginosa rhamnolipid, há um importante detergente biológico, que se acredita estar envolvido no desenvolvimento do biofilme e na comunicação intercelular. Dissolve rapidamente os surfactantes pulmonares que são facilmente catalisados pelas fosfolipases e, dessa maneira, estão envolvidos na infecção pulmonar aguda. Objetivo: O trabalho de pesquisa foi desenhado para investigar a virulência e o gene associado à virulência em P. aeruginosa responsável por infecções pulmonares. Métodos: No presente estudo, a reação em cadeia da polimerase (PCR) foi utilizada para a detecção do gene rhlR (codificação ramnolipídeo) de cepas isoladas. Foram realizados vários ensaios que garantiram seu comportamento virulento. O método de difusão em disco foi utilizado para verificar sua resistência a antibióticos. As estirpes isoladas foram resistentes a vários antibióticos aplicados. Resultado: Verificou-se que os homens são mais propensos a infecções respiratórias em comparação às mulheres. Membros do sexo masculino com idade entre 44 e 58 e 59 e 73 anos correm maior risco, enquanto mulheres com idade entre 44 e 58 anos também correm risco de infecções pulmonares. A resistência aos antibióticos foi observada medindo a zona de inibição nas cepas GCU-SG-M4, GCU-SG-M3, GCU-SG-M5, GCU-SG-M2, GCU-SG-M1 e GCU-SG-M6. O GCU-SG-M2 foi resistente ao fluconazol (FLU), claritromicina (CLR), cefixima (CFM) e penicilina (P10). Nenhuma zona de inibição foi observada. Mas se notou uma zona difusa incomum ao redor dos discos antibióticos Ak e MEM. Os genes rhl R e 16s rRNA foram caracterizados e analisados. Conclusão: As conclusões do presente estudo ajudariam a aumentar a conscientização sobre a resistência a antibióticos de, [...].

Síndrome de la uña verde: revisión actualizada de una patología emergente en la era COVID-19 / 19Green nail syndrome: updated review of an emerging disease in the era of COVID-19

El síndrome de la uña verde o cloroniquia corresponde a la infección por Pseudomonas aeruginosa de una lámina ungueal dañada en pacientes con algún factor de riesgo identificable, siendo los más frecuentes la inmunosupresión, el ambiente húmedo constante y la patología ungueal preexistente. Su diagnóstico es relativamente sencillo si se logra observar la tríada característica de coloración verdosa de la lámina ungueal, paroniquia proximal crónica y onicolisis distal; en casos de duda diagnóstica se puede enviar una muestra de la uña afectada para cultivos o estudio histopatológico. El pilar de su tratamiento corresponde al uso de antibióticos tópicos o sistémicos en conjunto con medidas generales que protejan de la humedad. Es muy importante enfatizar la prevención de esta patología en el personal de salud, especialmente en el contexto del lavado de manos frecuente y riguroso implementado durante la pandemia COVID-19, ya que existen reportes de transmisión nosocomial de P. aeruginosa por profesionales de la salud con infección ungueal.(AU)

Green nail syndrome or chloronychia is the infection of a damaged nail plate by Pseudomonas aeruginosa in a patient with an identifiable risk factor; the most frequently described are immunosuppression, a persistent moist environment and preexisting nail disease. Its diagnosis is relatively simple if the characteristic triad of green discoloration of the nail plate, chronic proximal paronychia and distal onycholysis can be observed, in cases of doubt a sample of the affected nail can be sent for cultures or histopathology. The cornerstone of treatment is the use of topical or systemic antibiotics along with measures to protect the nail from moisture. Prevention of this disease must be emphasized in health care personnel, especially in the context of frequent and rigorous handwashing practices implemented during the COVID-19 pandemic, since there are reports of nosocomial transmission of P. aeruginosaby health care professionals with nail infection.(AU)

Primer aislado de Pseudomonas aeruginosa productora de Sao Paulo metalo-beta-lactamasa (SPM-1) en un paciente chileno / First isolate of SPM-1- producing Pseudomonas aeruginosa (Sao Paulo metallo-beta-lactamase) in a Chilean patient

Resumen Las enzimas VIM, IMP, y NDM son carbapenemasas de tipo metalo-beta-lactamasas (MBLs) que se encuentran ampliamente distribuidas en el mundo. La SPM-1 (Sao Paulo metalo-beta-lactamasa) es una MBL que fue descrita en Pseudomonas aeruginosa en Sao Paulo (Brasil) en 2002. Comunicamos por primera vez la presencia de SPM-1 en Chile, en un aislado de P aeruginosa resistente a meropenem e imipenem, detectado en un cultivo rectal de vigilancia de carbapenemasas desde un paciente internado en nuestra institución. La secuencia del producto de la RPC fue 100% idéntica a la secuencia de SPM-1 reportada en Brasil. El paciente tenía antecedentes de una angioplastía realizada en Brasil en 2004-2005. Como consecuencia de este hallazgo, la detección de SPM mediante RPC será incorporada a la búsqueda de rutina de carbapenemasas en P aeruginosa.

Abstract VIM, IMP, and NDM carbapenemases are metallo-beta-lactamases (MBLs) that are widely distributed throughout the world. SPM-1 (Sao Paulo metallo-beta-lactamase) is an MBL that was described in Pseudomonas aeruginosa in Sao Paulo (Brazil) in 2002. We report for the first time the presence of SPM-1 in Chile, in an isolate of P aeruginosa resistant to meropenem and imipenem, detected in a carbapenemase surveillance rectal swab culture, in a patient admitted to our institution. The sequence of the PCR product was 100% identical to the sequence of SPM-1 reported in Brazil. The patient had a history of an angioplasty performed in Brazil in 2004-2005. As a consequence of this finding, the detection of SPM by PCR will be incorporated into the routine screening for carbapenemases in P aeruginosa.

Caracterización molecular de carbapenemasas en bacilos gramnegativos circulantes en hospitales de Paraguay. Primer cuatrimestre 2021 / Molecular characterization of carbapenemases in Gram-negative bacilli circulating in hospitals of Paraguay. First quarter of 2021

La resistencia a los antimicrobianos (RAM), representa un grave problema por el uso indiscriminado de antimicrobianos de amplio espectro. En nuestro país, durante el primer cuatrimestre del año, se observó un aumento inusual en el número de aislamiento de gérmenes multirresistentes, sobre todo de bacilos gramnegativos, los cuales fueron remitidos al laboratorio de referencia con el objetivo de caracterizar los genes de resistencia a los carbapenemes. Estudio observacional y prospectivo de corte transversal en 456 aislamientos de bacilos gramnegativos provenientes de 11 centros colaboradores de la Red Nacional de Vigilancia de la RAM, remitidos al Laboratorio Central de Salud Pública entre enero y abril de 2021, para la detección molecular (reacción en cadena de la polimerasa múltiple) de los genes de resistencia enzimática bla OXA-51, bla OXA-23, bla OXA-24, bla OXA-48, bla OXA-58, bla NDM, bla KPC, bla IMP, bla VIM. Trescientos sesenta correspondieron a bacilos gramnegativos no fermentadores: 346 Acinetobacter baumannii y 14 Pseudomonas aeruginosa; 96 fueron miembros de Enterobacterales, siendo prevalente Klebsiella pneumoniae (81). Todos los aislamientos de Acinetobacter baumannii resultaron ser productores de carbapenemasas: OXA-23 (94%), NDM (4%), NMD+OXA-58 (2%); en Pseudomonas aeruginosa, 7 de los 14 aislamientos (50%) fueron portadores de metalobetalactamasa del genotipo NDM (100%). Los genotipos NDM (92%) y KPC (8%) fueron confirmados en Enterobacterales. La resistencia plasmídica a carbapenemes es endémica en nuestro país, siendo prevalentes los genotipos OXA-23 en Acinetobacter baumannii y NDM en Pseudomonas aeruginosa y Enterobacterales

Antimicrobial resistance (AMR) represents a serious problem due to the indiscriminate use of broad-spectrum antimicrobials. During the first quarter of the year, an unusual increase in the number of isolation multi-resistant germs, especially gram-negative bacilli was observed, specially of Gram-negative bacilli which were referred to the reference laboratory in order to characterize the carbapenems resistance genes. Observational and prospective cross-sectional study in 456 isolates of Gram-negative bacilli from 11 collaborating centers of the National AMR Surveillance Network, referred to the Central Public Health Laboratory (LCSP) between January and April 2021, for molecular detection (multiple polymerase chain reaction) targeting the enzymatic resistance genes: bla OXA-51, bla OXA-23, bla OXA-24, bla OXA-48, bla OXA-58, bla NDM, bla KPC, bla IMP, bla VIM. Of the 456 isolates studied, 360 corresponded to non-fermenting Gram-negative bacilli, of which 346 were confirmed as Acinetobacter baumannii and 14 Pseudomonas aeruginosa; 96 were Enterobacterales, being Klebsiella pneumoniae (81) the most prevalent. All isolates of Acinetobacter baumannii carried genes encoding carbapenemases, being the OXA-23 (94%) followed by NDM (4%) and NDM +OXA-58 (2%). In Pseudomonas aeruginosa strains, 7 of the 14 isolates (50%) were carriers of NDM metallobetalactamase (100%). No carbapenemase gene was detected in the remaining 7. In all Enterobacterales strains, the presence of carbapenemases of the NDM (92%) and KPC (8%) genotypes were confirmed. Plasmid resistance to carbapenems is endemic in our country, being the OXA-23 genotypes prevalent in Acinetobacter baumannii and NDM in Pseudomonas aeruginosa and Enterobacterales

Resistencia enzimática en Pseudomonas aeruginosa, aspectos clínicos y de laboratorio / Enzymatic resistance in Pseudomonas aeruginosa, clinical and laboratory aspects

Resumen Pseudomonas aeruginosa es uno de los principales patógenos que causa infecciones asociadas a la atención en salud (IAAS). Su capacidad de adaptación, diseminación, resistencia intrínseca a los antimicrobianos y de adquirir nuevos mecanismos a través de elementos genéticos móviles, hacen que el tratamiento de las infecciones por este microorganismo sea un desafío para el médico clínico. Intrínsecamente, P. aeruginosa, presenta una reducida permeabilidad en la membrana externa, debido a la expresión de bombas de expulsión, y una cefalosporinasa tipo AmpC inducible. Además, P. aeruginosa es capaz de adquirir nuevos determinantes de resistencia por transferencia horizontal en forma de casetes situados en integrones, y a su vez, localizados en transposones o plásmidos. Dentro de la resistencia enzimática que presenta P. aeruginosa destacan las β-lactamasas, incluyendo aquellas de espectro extendido (BLEE) y las carbapenemasas. Pero también enzimas modificadoras de los aminoglucósidos, haciendo que este microorganismo pueda presentar fenotipos de multi-resistencia (MDR), resistencia extrema (XDR) y panresistencia (PDR) a los antimicrobianos denominados antipseudomonas, incluyendo a las nuevas cefalosporinas con inhibidores de beta-lactamasas.

Abstract Pseudomonas aeruginosa is one of the major pathogens causing healthcare-associated infections (HAI). Its capacity of adaptation, dissemination, intrinsic resistance to antimicrobials and of acquiring new mechanisms through mobile genetic elements, make the treatment of infections by this microorganism a challenge for the clinician. Intrinsically, P. aeruginosa, presents a reduced permeability in the external membrane, due to the expression of efflux pumps, and an inducible AmpC-type cephalosporinase. In addition, P. aeruginosa is able to acquire new resistance determinants by horizontal transfer in the form of cassettes located in integrons, and in turn located in transposons or plasmids. Within the enzymatic resistance that P. aeruginosa presents, betalactamases, including extended spectrum (ESBL) and carbapenemases. But also aminoglycoside modifying enzymes, stand out, causing this microorganism to present multi-resistance phenotypes (MDR), extreme resistance (XDR) and pan-resistance (PDR) to the called antipseudomonal antibiotics, including the new cephalosporins with betalactamase inhibitors.

Carbapenemasas en aislamientos de Pseudomonas aeruginosa resistentes a carbapenémicos aisladas en hospitales de Chile

Resumen Introducción: La resistencia a carbapenémicos mediada por carbapenemasas en Pseudomonas aeruginosa es un mecanismo importante; sin embargo, la pérdida de la porina OprD continúa siendo el mecanismo más frecuente. Objetivo: Determinar la proporción de aislados de P. aeruginosa, resistentes a imipenem y/o meropenem, productores de carbapenemasas, el tipo de enzima producida y la relación genética entre los aislados. Material y Métodos: Se incluyó 113 aislados resistentes al menos a un carbapenémico, provenientes de 12 hospitales de 9 ciudades de Chile. Adicionalmente se determinó la susceptibilidad a ceftazidima, amikacina, gentamicina, piperacilina/tazobactam, ciprofloxacina y colistina. Se realizó Carba NP y en los aislados positivos (n: 61) se detectó genes de carbapenemasas por RPC. Los aislados fueron tipificados por restricción con SpeI y PFGE. Resultados: No todos los aislados presentan carbapenemasas, y sólo en 61/113 de ellos (54%) se amplificó blaKPC (32) o blaVIM (29). En ninguno de los aislados se encontró co-portación de ambos genes. Los pulsotipos indican que no hay diseminación clonal de los aislados, evidenciando una importante diversidad genética. Conclusiones: Los aislados de P. aeruginosa productores de carbapenemasas, obtenidos en hospitales de Chile, portan genes blaKPC y blaVIM y, en su mayoría, son policlonales. Estos resultados ponen énfasis en la importancia de realizar estudios epidemiológicos con mayor número de aislados que permitan conocer mejor la epidemiología de P. aeruginosa productoras de carbapenemasas en Chile.

Abstract Background: Carbapenem resistance mediated by carbapenemases in Pseudomonas aeruginosa is an important mechanism; however, loss of porin OprD remains as the most frequent. Aim: To determine the proportion of P. aeruginosa isolates, resistant to imipenem and/or meropenem, producing carbapenemases, the type of enzyme produced and the genetic relationship between the isolates. Methods: One hundred and thirteen resistant to at least one carbapenem isolates, obtained in 12 hospitals and 9 cities in Chile were studied. Additionally, susceptibility to ceftazidime, amikacin, gentamicin, piperacillin/tazobactam, ciprofloxacin and colistin was determined. Carba NP was performed and in the positive isolates carbapenemase genes were detected by PCR. The isolates were typified by restriction with SpeI and PFGE. Results: Not all isolates produce carbapenemases, and only in 61/113 of them (54%) the blaKPC (32) or blaVIM (29) was amplified. In none of the isolates was found the coharboring of both genes. The pulsotypes indicated no clonal dissemination of the isolates, evidencing an important genetic diversity. Conclusions: P. aeruginosa isolates producing carbapenemases, obtained in Chilean hospitals carry blaKPC and blaVIM genes and, mostly, are polyclonal. These results emphasize the importance of carrying out epidemiological studies with a greater number of isolates to allow a better understanding of the epidemiology of carbapenemase-producing P. aeruginosa in Chile.

Prevalence of antibiotic resistance and virulent factors in nosocomial clinical isolates of Pseudomonas aeruginosa from Panamá

ABSTRACT Background: Pseudomonas aeruginosa is an important causative agent of nosocomial infections. As pathogen, P. aeruginosa is of increasing clinical importance due to its ability to develop high-level multidrug resistance (MDR). Methods: The aim of the present study was to better understand the intrinsic virulence of circulating strains of Pseudomonas aeruginosa, by surveying and characterizing the antibiotic resistance profiles and prevalence of virulence factors in 51 clinical isolates of P. aeruginosa obtained from children admitted to Hospital del Niño-Panamá during the period of October 2016 until March 2017. Antimicrobial susceptibilities were assessed by determining the minimum inhibitory concentration for 12 antibiotics against P. aeruginosa clinical isolates using the VITEK system (https://www.biomerieux.com). Additionally, all isolates were examined by Polymerase Chain Reaction (PCR) for the presence of components of the MexAB-OprM efflux pump system (mexABR) and pyoverdine receptor genes and betalactamases resistance genes (ESBL) using gene-specific primers. Results: A total of 51 pyoverdine producing clinical isolates were analyzed, all of which expressed resistance genes such as genes of the MexAB-OprM efflux pump system (mexABR) and pyoverdine receptor genes (fpvA). Out of 51 MDR isolates, 22 were ESBL producers. The most common ESBL gene was blaTEM expressed by 43% of the isolates. The isolates tested in this study showed increased resistance to antibiotics in the following categories: (i) penicillins (ampicillin (69%), piperacillin (22%); (ii) pyrimethamines (trimethoprim, 65%); (iii) nitrofurans (nitrofurantoin, 63%), and (iv) third-generation cephalosporin cefotaxime (53%). These results underscore a high prevalence of MDR amongst clinical isolates from Panama. Conclusions: The present study indicates that prevalence of BlaTEM-carrying strains is increasing with subsequent multidrug resistance in Panamá and as well reported worldwide. The virulent factors identified in this study provide valuable information regarding the prevalence of resistance genes and their potential impact on treatments that exploit the unique physiology of the pathogen. To prevent further spread of MDR, the proportions of resistant strains of Pseudomonas aeruginosa should be constantly evaluated on healthcare institutions of Panamá. More importantly, this information can be used to better understand the evolution and dissemination of strains hoping to prevent the development of resistance in Pseudomonas aeruginosa. Future studies quantifying the expression of these virulent genes will emphasize on the acquisition of multidrug resistance.

Molecular epidemiology of Pseudomonas aeruginosa isolated from lower respiratory tract of ICU patients / Epidemiologia molecular de Pseudomonas aeruginosa isolada em pacientes com infecções do trato respiratório inferior admitidos em UTI

Lower respiratory tract infections (LRTIs) caused by Pseudomonas aeruginosa are the most common infection among hospitalized patients, associated with increased levels of morbidity, mortality and attributable health care costs. Increased resistant Pseudomonas worldwide has been quite meaningful to patients, especially in intensive care unit (ICUs). Different species of Pseudomonas exhibit different genetic profile and varied drug resistance. The present study determines the molecular epidemiology through DNA fingerprinting method and drug resistance of P. aeruginosa isolated from patients with LTRIs admitted in ICU. A total of 79 P. aeruginosa isolated from patients with LRTIs admitted in ICU were characterized by Restriction Fragment Length Polymorphism (RFLP), Random Amplified Polymorphic DNA (RAPD) and Repetitive Extrapalindromic PCR (REP-PCR). Antibiotic resistance was determined by minimum inhibitory concentration (MIC) assay while MDR genes, viz, blaTEM, blaOXA, blaVIM, blaCTX-M-15 were detected by polymerase chain reaction (PCR). Of the 137 Pseudomonas sp isolated from ICU patients, 57.7% of the isolates were reported to be P. aeruginosa. The overall prevalence of P. aeruginosa among the all included patients was 34.5%. The RAPD analysis yielded 45 different patterns with 72 clusters with 57% to 100% similarity level. The RFLP analysis yielded 8 different patterns with 14 clusters with 76% to 100% similarity level. The REP PCR analysis yielded 37 different patterns with 65 clusters with 56% to 100% similarity level. There was no correlation among the different DNA patterns observed between the three different methods. Predominant of the isolates (46.8%) were resistant to amikacin. Of the 79 isolates, 60.8% were positive for blaTEM gene and 39.2% were positive for blaOXA gene. P. aeruginosa was predominantly isolated from patients with LRTIs admitted in ICU. The difference in the similarity level observed between the three DNA fingerprinting methods indicates that there is high inter-strain variability. The high genetic variability and resistance patterns indicates that we should continuously monitor the trend in the prevalence and antibiotic resistance of P. aeruginosa especially in patients with LRTIs admitted in ICU.

Infecções do trato respiratório inferior (ITRIs) são as infecções mais comuns entre pacientes internados em unidade de terapia intensiva (UTI). Pseudomonas aeruginosa é a causa mais comum de ITRIs e está associada ao aumento da mortalidade. Diferentes espécies de Pseudomonas exibem diferentes perfis genéticos e resistência variada as drogas. O presente estudo determina a epidemiologia molecular através do método de fingerprinting de DNA e resistência as drogas de P. aeruginosa isoladas de pacientes com LTRIs internados em UTI. Um total de 79 P. aeruginosa isoladas de pacientes com ITRIs internados em UTI foram caracterizados por Polimorfismo de Comprimento de Fragmentos de Restrição (RFLP), DNA Polimórfico Amplificado ao Acaso (RAPD) e PCR Extrapalindrômico Repetitivo (REP-PCR). A resistência aos antibióticos foram determinadas pelos ensaios de concentrações inibitória mínima (MIC), enquanto os genes MDR, blaTEM, blaOXA, blaVIM, blaCTX-M-15 foram detectados pela reação em cadeia da polimerase (PCR). Das 137 Pseudomonas sp isoladas de pacientes de UTI, 57,7% dos isolados foram relatados como P. aeruginosa. A prevalência geral de P. aeruginosa entre os pacientes incluídos foram de 34,5%. A análise RAPD renderam 45 padrões diferentes com 72 clusters com nível de similaridade de 57% a 100%. A análise RFLP renderam 8 padrões diferentes com 14 clusters com 76% a 100% de similaridade. A análise de PCR do REP produziram 37 padrões diferentes com 65 clusters com nível de similaridade de 56% a 100%. Não houveram correlações entre os diferentes padrões de DNA observados entre os três diferentes métodos. Predominantes dos isolados (46,8%) eram resistentes à amicacina. Dos 79 isolados, 60,8% foram positivos para o gene blaTEM e 39,2% foram positivos para o gene blaOXA. P. aeruginosa foi predominantemente isolado de pacientes com ITRIs internados em UTI. A diferença no nível de similaridade observado entre os três métodos de fingerprinting do DNA indica que há alta variabilidade inter-strain. A alta variabilidade genética e os padrões de resistência indicam que devemos monitorar continuamente a tendência na prevalência e resistência a antibióticos de P. aeruginosa, especialmente em pacientes com ITRIs internados em UTI.

Isolation of and risk factors for airway infection with Pseudomonas aeruginosa in patients with non-cystic fibrosis bronchiectasis / Isolamento de Pseudomonas aeruginosa e fatores de risco de infecção das vias aéreas pela bactéria em pacientes com bronquiectasias não fibrocísticas

ABSTRACT Objective: To identify microorganisms in sputum samples of patients with stable non-cystic fibrosis bronchiectasis and to determine risk factors related to the isolation of Pseudomonas aeruginosa (PA) in those patients. Methods: Consecutive patients were recruited from a tertiary hospital outpatient clinic in the city of Fortaleza, Brazil. The patients were submitted to spirometry, six-minute walk test, HRCT, and sputum collection. Data on serum fibrinogen levels, disease severity, sputum color, and history of azithromycin treatment were collected. Results: The study included 112 patients, and females predominated (68%). The mean age was 51.6 ± 17.4 years. Most patients presented with mild-to-moderate disease (83%). The mean six-minute walk distance was 468.8 ± 87.9 m. Mean FEV1 and FVC, in % of predicted values, were 60.4 ± 21.8% and 69.9 ± 18.5%, respectively. The mean serum fibrinogen level was 396.1 ± 76.3 mg/dL. PA was isolated in 47 patients, other potentially pathogenic microorganisms (PPMs) were isolated in 31 patients, and non-PPMs were isolated in 34 patients. Purulent sputum was identified in 77 patients (68%). The patients with PA, when compared with those without it, presented with more severe disease, higher serum fibrinogen levels, and lower FVC%. In addition, purulent sputum and long-term azithromycin treatment were more common in those with PA. The multivariate regression analysis showed that the independent factors associated with PA were serum fibrinogen level > 400 mg/dL (OR = 3.0; 95% CI: 1.1-7.7) and purulent sputum (OR = 4.3; 95% CI: 1.6-11.3). Conclusions: In our sample, the prevalence of PA in sputum was 42%. Sputum color and inflammatory markers were able to predict the isolation of PA, emphasizing the importance of routine sputum monitoring.

RESUMO Objetivo: Identificar microrganismos em amostras de escarro de pacientes com bronquiectasia não fibrocística estável e determinar os fatores de risco relacionados com o isolamento de Pseudomonas aeruginosa (PA) nesses pacientes. Métodos: Pacientes consecutivos foram recrutados em um ambulatório de um hospital terciário em Fortaleza (CE). Os pacientes foram submetidos a espirometria, teste de caminhada de seis minutos, TCAR e coleta de escarro. Foram coletados dados referentes ao fibrinogênio sérico, gravidade da doença, cor do escarro e histórico de tratamento com azitromicina. Resultados: O estudo incluiu 112 pacientes, com predomínio do sexo feminino (68%). A média de idade foi de 51,6 ± 17,4 anos. A maioria dos pacientes apresentou doença leve a moderada (83%). A média da distância percorrida no teste de caminhada de seis minutos foi de 468,8 ± 87,9 m. A média do VEF1 em % do previsto foi de 60,4 ± 21,8%, e a da CVF em % do previsto foi de 69,9 ± 18,5%. A média do fibrinogênio sérico foi de 396,1 ± 76,3 mg/dL. PA foi isolada em 47 pacientes; outros microrganismos potencialmente patogênicos (MPP) foram isolados em 31; não MPP foram isolados em 34. Escarro purulento foi identificado em 77 pacientes (68%). Os pacientes com PA, em comparação com aqueles sem, apresentaram doença mais grave, fibrinogênio sérico mais elevado e menor CVF%. Além disso, escarro purulento e tratamento prolongado com azitromicina foram mais comuns naqueles com PA. A análise de regressão multivariada mostrou que os fatores independentes relacionados com PA foram fibrinogênio sérico > 400 mg/dL (OR = 3,0; IC95%: 1,1-7,7) e escarro purulento (OR = 4,3; IC95%: 1,6-11,3). Conclusões: Em nossa amostra, a prevalência de PA no escarro foi de 42%. A cor do escarro e os marcadores inflamatórios foram capazes de prever o isolamento de PA, o que enfatiza a importância do monitoramento rotineiro do escarro.

Resistência aos antimicrobianos e diversidade genética de variantes fenotípicas de Pseudomonas aeruginosa não sensíveis aos carbapenêmicos recuperadas de pacientes com fibrose cística com infecção pulmonar crônica: uma análise temporal / Antimicrobial resistance and genetic diversity of phenotypic variants of carbapenem non susceptible Pseudomonas aeruginosa recovered from patients with cystic fibrosis with chronic lung infection: a temporal analysis

Pseudomonas aeruginosa, bactéria ubíqua e versátil, pode se comportar como um patógeno oportunista, com ampla capacidade adaptativa, por múltiplos fatores de virulência e resistência. Como agente patogênico nas infecções pulmonares em pacientes com fibrose cística (FC), é motivo de prognóstico ruim, aumento de hospitalizações e altas taxas de morbimortalidade, sendo quase impossível a sua erradicação, ao evoluírem para a cronicidade. Globalmente, é notável o aumento nos índices de amostras não sensíveis aos carbapenêmicos e a múltiplos antimicrobianos, essenciais à terapêutica. Assim, avaliamos temporalmente a susceptibilidade aos antimicrobianos e a presença de amostras hipermutáveis (HPM) em P. aeruginosa de diferentes morfotipos, não sensíveis aos carbapenêmicos (PANSC), obtidas de pacientes FC com infecção pulmonar crônica, acompanhados em dois centros de referência no Rio de Janeiro. De 2007 a 2016, a análise retrospectiva, através dos resultados obtidos no teste de disco-difusão (TDD), permitiu selecionar amostras de PANSC incluídas neste trabalho. Usando os resultados obtidos no TDD, foi definida a susceptibilidade a outros antimicrobianos, bem como os fenótipos de resistência, multi-(MDR), extensivo-(XDR) e pandroga resistentes (PDR). Adicionalmente, determinou-se a concentração inibitória mínima (CIM) para imipenem (IPM), meropenem (MEM), doripenem (DOR) e polimixina (POL). Através de teste fenotípico, foi calculada a frequência de mutação espontânea e as amostras hipermutáveis foram caracterizadas. O sequenciamento de genoma total (SGT) foi realizado em seis amostras de diferentes morfotipos, incluindo uma variante fenotípica rara, a small colony variant (SCV). Essas amostras foram recuperadas em dois episódios de exacerbação do paciente. Foram investigadas a clonalidade, resistência a antimicrobianos e virulência. Das 143 amostras, de 18 pacientes (9 pediátricos e 9 adultos), os resultados do TDD apontaram taxas de não susceptibilidade superiores a 44% para gentamicina, amicacina, tobramicina e ciprofloxacina, e maiores de 30 % para POL. Pela determinação da CIM, quase a totalidade (96%) das amostras foram não sensíveis a IMP, seguidos de 56% para MEM e 44% para DOR. Analisando-se a distribuição dos valores da CIM50 e CIM90 nos dois grupos de pacientes, os valores para IMP foram maiores entre as amostras dos pacientes pediátricos, equivalendo a 32 µg/mL e 64 µg/mL, respectivamente. Cerca de 25%, 37% e 6% eram MDR, XDR e PDR, respectivamente. Aproximadamente 12% eram HPM, e mais da metade destas foram XDR. Após o SGT, as seis amostras, recuperadas do caso clínico foram classificadas em um novo sequence type (ST2744), com a presença de genes de resistência adquiridos blaPAO, blaOXA-50, aph(3')-Iib, fosA, catB7 e crpP, apresentando mutações em genes codificadores de porinas e bombas de efluxo. Entretanto, não foram observados marcadores genéticos clássicos exclusivos para os fenótipos SCV e HPM. Este é o primeiro relato de P. aeruginosa SCV na FC, no Brasil. A vigilância epidemiológica de P. aeruginosa é crucial para a conduta terapêutica, bem como para o sucesso da resposta do paciente e erradicação da infecção pulmonar, justificando o uso de técnicas fenotípicas e moleculares na detecção dos mecanismos de resistência e virulência desse microrganismo na FC.

Pseudomonas aeruginosa, a ubiquitous and versatile bacterium, can behave as an opportunistic pathogen, with strong adaptive capacity, due to multiple virulence and resistance factors. As a pulmonary infection pathogen in patients with cystic fibrosis (CF), it is related with poor prognosis, increased hospitalizations and high rates of morbidity and mortality, and the eradication is almost impossible, especially after chronicity. The increase rates of isolates non-susceptible to carbapenem and multiple antimicrobials, essentials to therapy, have been observed worldwide. Therefore, we assessed the antimicrobial susceptibility and the presence of hypermutability (HPM) in non-susceptible to carbapenem P. aeruginosa (PANSC) isolates from different morphotypes, obtained from CF patients with chronic pulmonary infection, followed at two reference centers in Rio de Janeiro. Using the results obtained by disk-diffusion test (DDT) between 2007 to 2016, we select 143 PANSC and susceptibility to other antimicrobials was defined, as well as the resistance phenotypes, multi- (MDR), extensive- (XDR) and pandrug resistant (PDR). Additionally, the minimum inhibitory concentration (MIC) for imipenem (IPM), meropenem (MEM), doripenem (DOR) and polymyxin (POL) was determined. Hypermutable isolates were characterized by determination of mutation frequency. Whole genome sequencing (WGS) was performed in six morphotypes isolates, including the small colony variant (SCV), a rare variant phenotype. These isolates were recovered in two exacerbation episodes. Clonality, antimicrobial resistance and virulence were investigated. Of the total (143 isolates) isolated from 18 patients (9 pediatric and 9 adults), non-susceptibility rates above than 44% for gentamicin, amikacin, tobramycin and ciprofloxacin, and more than 30% for POL were observed. Almost all (96%) of the isolates were non-susceptible to IPM by MIC determination, followed by 56% for MEM and 44% for DOR. MIC50 (32 µg/mL) and MIC90 (64 µg/mL) rates for IPM were higher among pediatric patient isolates and 25%, 37% and 6% were MDR, XDR and PDR, respectively. 12% of all isolates were classified as HPM and more than half were categorized as XDR. Using WGS, the six isolates recovered from the clinical case, were identified as a new sequence type (ST2744). Acquired resistance genes blaPAO, blaOXA-50, aph (3')-Iib, fosA, catB7 and crpP and mutations in encoding genes for porins and efflux pumps, was annotated. None exclusive classic genetic markers related to SCV and HPM phenotypes were not observed. This is the first Brazilian report of P. aeruginosa SCV in CF. Our results highlight the importance of epidemiological surveillance in P. aeruginosa. The application of phenotypic and molecular techniques to investigate resistance and virulence mechanisms, can contribute to therapeutic success in CF.

Colistina en el tratamiento de infecciones por pseudomonas aeruginosa y acinetobacter baumannii extensivamente resistentes (XDR) en un hospital de tercer nivel / Colistin-based treatment for extensively drug resistant (XDR) Pseudomonas aeruginosa and Acinetobacter baumannii infection at a third level hospital

Resumen Objetivo: Describir la respuesta clínica y mortalidad general de Colistina en infecciones por Pseudomonas XDR y Acinetobacter XDR en el Hospital Nacional Arzobispo Loayza in Lima, Peru. Métodos: Estudio observacional, descriptivo y retrospectivo. Se incluyeron los registros de pacientes > 18 años, desde junio del 2014 a junio del 2016, que tuvieron infección por Pseudomonas XDR o Acinetobacter XDR confirmada por cultivo, y que recibieron colistina. Se realizó análisis univariado de las características generales de los pacientes; un análisis bivariado con test de Chi2 , t-student o ANOVA según corresponda, y además se describió los factores asociados a mortalidad. Resultados. Se incluyeron 56 registros de pacientes, la mediana de la edad fue 46,5 [31,5 a 63,5]. El 48,2% tuvo un cultivo positivo para Pseudomonas XDR y el 51,8% para Acinetobacter XDR. La respuesta clínica favorable fue 85,7% a los 15 días y de 78,6% a los 30 días. La mortalidad intrahospitalaria a los 30 días fue 21,4%, la mortalidad en UCI fue de 30,8% y la nefrotoxicidad fue de 5,4%. Conclusiones. Colistina combinada con otro antimicrobiano tuvo una respuesta clínica favorable en infección por Pseudomonas XDR o Acinetobacter XDR.

Abstract Objective: To describe the clinical response and overall mortality of Colistin in infections by Pseudomonas XDR and Acinetobacter XDR at the Hospital Nacional Arzobispo Loayza in Lima, Peru. Methods: Observational, descriptive, retrospective study. Records of all patients > 18 years old, from June 2014 to June 2016, who had infection by Pseudomonas XDR or Acinetobacter XDR confirmed by culture, and who received colistin, were included. A univariate analysis of the general characteristics of the patients was performed; a bivariate analysis with a Chi2, t-student or ANOVA test as appropriate, and the factors associated with mortality were also determined. Results: 56 patient records were included; the median age was 46,5 [31,5 to 63,5]. The Culture was positive for Pseudomonas XDR in 48,2% and for Acinetobacter XDR in 51,8%. The favorable clinical response was 85,7% at 15 days and 78,6% at 30 days. In-hospital mortality at 30 days was 21,4%, ICU mortality was 30,8% and nephrotoxicity was 5,4%. Conclusions: Colistin combined with another antimicrobial had a favorable clinical response in infection with Pseudomonas XDR and Acinetobacter XDR.

Ectima gangrenoso, manifestación cutánea infrecuente de una infección por diversos agentes / Ecthyma gangrenosum, a rare cutaneous manifestation of infection by various agents

El ectima gangrenoso es un trastorno infeccioso infrecuente clásicamente relacionado a bacteriemia, descrito principalmente en poblaciones inmunodeprimidas. El agente más comúnmente relacionado es Pseudomonas aeruginosa, sin embargo, se han descrito otras etiologías bacterianas, hongos filamentosos y levaduras. Su patogénesis está dada por la invasión de la pared de los vasos sanguíneos, causando trombosis arterial y venosa, desencadenando necrosis de epidermis y tejidos subdérmicos. Clínicamente, se manifiesta como máculas, vesículas o pústulas hemorrágicas que evolucionan a úlceras de superficie necrótica rodeadas por un halo eritematoso característico, habitualmente en un contexto clínico de sepsis. El diagnóstico de este cuadro es clínico, sin embargo, el estudio microbiológico es clave en la identificación del agente etiológico y un posterior tratamiento dirigido. En su manejo es esencial una alta sospecha clínica y el inicio de tratamiento antibiótico en forma precoz. La duración del tratamiento es variable y en algunos casos debe asociarse a debridación quirúrgica. El pronóstico es variable dependiendo de múltiples factores: estado inmunológico, agente etiológico, presencia de sepsis y el tiempo de inicio de tratamiento.(AU)

Ecthyma gangrenosum is an infrequent infectious disorder classically related to bacteremia, described mainly in immunosuppressed populations. The most related agent is Pseudomonas aeruginosa, however other bacterial etiologies, filamentous fungi and yeasts have been described. Its pathogenesis is given by the invasion of the blood vessel wall, causing arterial and venous thrombosis, triggering necrosis of epidermis and subdermal tissues. Clinically, it manifests as hemorrhagic macules, vesicles or pustules that evolve into ulcers with a necrotic surface surrounded by a characteristic erythematous halo, usually in a clinical setting of sepsis. The diagnosis of this condition is clinical, however the microbiological study is key in the identification of the etiological agent and a subsequent directed treatment. In its management, a high clinical suspicion and an early start of antibiotic treatment are essential. The duration of treatment is variable and in some cases it must be associated with surgical debridement. The prognosis is variable depending on multiple factors: immunological status, etiological agent, presence of sepsis and time of initiation of treatment.(AU)

Activity of ceftolozane-tazobactam and comparators against gram-negative bacilli: Results from the study for monitoring antimicrobial resistance trends (SMART - Brazil; 2016-2017)

Abstract Multi-drug resistant Gram-negative bacilli (GNB) have been reported as cause of serious hospital-acquired infections worldwide. The aim of this study was to investigate the in vitro activity of ceftolozane-tazobactam compared to other agents against GNB isolated from patients admitted to Brazilian medical centers between the years 2016 and 2017. Presence of β-lactamase encoding genes was also evaluated. Methods Antimicrobial susceptibility testing of GNB isolated from intra-abdominal (IAI), respiratory (RTI), and urinary tract infections (UTI) was performed according to ISO 227-1 guidelines and interpreted following CLSI and BrCAST/EUCAST guidelines. Qualifying Enterobacteriaceae isolates were screened for the presence of β-lactamase genes by PCR followed by DNA sequencing. Results 1748 GNB collected from UTI (45.2%), IAI (25.7%) and RTI (29.1%) were evaluated. Ceftolozane-tazobactam remained highly active (94.7%) against E. coli isolates. Among K. pneumoniae, susceptibility rates were 85.9% and 85.4% for amikacin and colistin, whereas ceftolozane-tazobactam (44.1% susceptible) and carbapenems (55.2-62.2% susceptible) showed poor activity due to bla KPC-2. Against E. cloacae amikacin, imipenem, and meropenem retained good activity (>90%). Ceftolozane-tazobactam was the most potent β-lactam agent tested against P. aeruginosa (90.9% susceptible), including ceftazidime and imipenem resistant isolates. β-lactamase encoding genes testing was carried out in 433 isolates. bla CTX-M variants were predominant in E. coli, P. mirabilis and E. cloacae. Among the K. pneumoniae molecularly tested, most carried bla KPC (68.5%), with all harboring bla KPC-2, except two isolates carrying bla KPC-3 or bla KPC-30. ESBL encoding genes, mainly CTX-M family, were frequently detected in K. pneumoniae, plasmid-mediated AmpC were rare. A variety of PDC encoding genes were detected in P. aeruginosa isolates with five isolates harboring MBL and one KPC encoding genes. Conclusion Ceftolozane-tazobactam was very active against E. coli, P. mirabilis and P. aeruginosa isolates and could constitute an excellent therapeutic option including for those isolates resistant to extended-spectrum cephalosporins and carbapenems but not producers of carbapenemases.

Neonatal infection and passive acquisition of serum total IgG and reactive with Streptococcus B, anti-LPS of Klebsiella spp and Pseudomonas spp antibodies in twins

SUMMARY OBJECTIVE To describe the concentration of total and specific IgG antibodies anti-Streptococcus B, anti-lipopolysaccharide of Klebsiella spp, and anti-lipopolysaccharide of Pseudomonas spp in the umbilical cord of newborn(NB) twins and to analyze the association between neonatal infection and antibody concentration in the umbilical cord blood. METHODS A prospective cross-sectional study of a cohort of NB twins admitted during the period of 20 months. Patients with malformations and mothers with infection were excluded. Variables analyzed: gestational age(GA); birth weight(BW); antibody concentrations in umbilical cord blood; infection episodes. We used the paired Student t-test, Spearman correlation, and generalized estimation equation. RESULTS 57 pairs of twins were included, 4 excluded, making the sample of 110 newborns. GA=36±1.65weeks and BW=2304.8±460g(mean±SD). Antibody concentrations in twins(mean±SD): total IgG=835.71±190.73mg/dL, anti-StreptococcusB IgG=250.66±295.1 AU/mL, anti-lipopolysaccharide of Pseudomonas spp IgG=280.04±498.66 AU/mL and anti-lipopolysaccharide of Klebsiella spp IgG=504.75±933.93 AU/mL. There was a positive correlation between maternal antibody levels and those observed in newborns(p <0.005). The transplacental transfer of maternal total IgG and anti-LPS Pseudomonas IgG antibodies was significantly lower at NB GA <34 weeks(p <0.05). Five newborns were diagnosed with an infection. Infants with infection had significantly lower total IgG concentration(p <0.05). CONCLUSION This study showed a positive correlation between maternal and newborn antibodies levels. In infants younger than 34 weeks there is less transfer of total IgG and anti-LPS Pseudomonas IgG. The highest incidence of infection in the newborn group who had significantly lower total IgG serum antibodies reinforces the importance of anti-infectious protection afforded by passive immunity transferred from the mother.

RESUMO OBJETIVOS Descrever o título de anticorpos IgG total e específico anti-Streptococcus B, anti-lipopolissacarídeos(LPS) de Klebsiella e Pseudomonas no cordão umbilical em gêmeos e analisar a possível associação entre os títulos desses anticorpos e a ocorrência de infecção. MÉTODOS Estudo prospectivo transversal de uma coorte de recém-nascidos (RN) gemelares em 20 meses. Excluídos: malformação, infecção congênita ou materna. Variáveis estudadas: idade gestacional(IG); peso de nascimento(PN); título de anticorpos e episódios de infecção. Foram utilizados testes t-Student pareado, correlação de Spearman e equações de estimação generalizadas. RESULTADOS Elegíveis 59 pares de gêmeos, excluídos 4 e incluídos 55 pares (n=110RN). A IG foi 36±1,65semanas e o PN foi 2304,8±460g (média±DP). Concentrações de anticorpos dos RN(média±DP): IgG total=835,71±190,73 mg/dL, IgG anti-Streptococcus B=295,1±250,66 UA/mL, IgG anti-LPS Pseudomonas=280,04±498,66 UA/mL e IgG anti-LPS Klebsiella=504,75± 933,93UA/mL. Houve correlação positiva entre níveis de anticorpos maternos e aqueles observados nos RN (p<0,005). A transferência transplacentária de anticorpos maternos IgG total e IgG anti-LPS Pseudomonas foi significativamente menor em RN IG < 34semanas (p<0,05). Foram diagnosticados 5 RN com infecção. Os RN que apresentaram infecção tinham concentração de IgG total significativamente menor (p<0,05). CONCLUSÕES Na população estudada existe correlação entre os anticorpos maternos e os níveis de anticorpos no RN. Nos gêmeos menores que 34 semanas há menor transferência de IgG total e IgG anti-LPS Pseudomonas. Nos RN com infecção a concentração de IgG total é significativamente menor, o que demonstra a maior vulnerabilidade e risco de infecção dessa população e a importância da imunidade passiva transferida pela placenta.

Phenotypic and genotypic analysis of biofilm production by Pseudomonas aeruginosa isolates from infection and colonization samples

Abstract INTRODUCTION: Pseudomonas aeruginosa is an opportunistic pathogen associated with healthcare-related infections, affecting mainly patients with underlying diseases and immunosuppression. This microorganism has several virulence mechanisms that favour its pathogenesis, including the production of biofilm. This study aimed to analyze the phenotypic production of biofilms, the occurrence of quorum sensing (QS) genes, and the clonal profile of clinical isolates of P. aeruginosa from colonized/infected patients in a tertiary hospital in Recife-PE. METHODS: We obtained 21 isolates that were classified as infection isolates (II), and 10 colonization isolates (CI). The phenotypic analysis for biofilm production was performed quantitatively. The QS genes were detected by specific PCRs, and the clonal profile was assessed using ERIC-PCR. RESULTS: Of the 31 isolates, 58.1 % (18/31) were biofilm producers, of which 70 % (7/10) were CI and classified as weakly adherent; 52.4 % (11/21) of the II produced biofilms, and were classified as weak (38.1 %, (8/21)), moderate (9.5 %, (2/21)), and strongly adherent (4.8 %, (1/21)). All isolates harbored the QS genes analyzed. In the clonal analysis, 26 distinct genetic profiles were identified, highlighting the presence of a clone in four samples, i.e., one infection isolate, and 3 colonization isolates. CONCLUSIONS: The detection of biofilm formation is important in P. aeruginosa in addition to the identification of colonization and infection isolates, especially from complex environments such as ICUs. Further, we define a strategy for monitoring and analyzing P. aeruginosa strains that can potentially cause infections in hospitalized patients.

Pseudomonas aeruginosa in the ICU: prevalence, resistance profile, and antimicrobial consumption

Abstract INTRODUCTION: Pseudomonas aeruginosa is one of the main pathogens causing infection in intensive care units (ICUs) and usually presents antimicrobial resistance. METHODS: Data were obtained from ICUs between 2010 and 2013. RESULTS: P. aeruginosa had a prevalence of 14.5% of which 48.7% were multidrug resistant. We observed increasing resistance to carbapenems and polymyxin B and growing consumption of aminoglycosides, meropenem, ceftazidime, and polymyxin B. The regression impact between resistance and consumption was significant with respect to amikacin, imipenem, meropenem, and polymyxin B. CONCLUSIONS: Monitoring antimicrobial consumption and resistant microorganisms should be reinforced to combat antimicrobial- and multi-drug resistance.

Effectiveness of a multistep Pseudomonas aeruginosa eradication treatment protocol in children with cystic fibrosis in Brazil / Efetividade de um protocolo de tratamento de erradicação em fases de Pseudomonas aeruginosa em crianças com fibrose cística no Brasil

ABSTRACT Objective: Although various strategies have been proposed for eradicating Pseudomonas aeruginosa in patients with cystic fibrosis (CF), only a few employ multistep treatment in children colonized by that pathogen for the first time. The aim of this study was to describe the effectiveness of a three-phase eradication protocol, initiated after the first isolation of P. aeruginosa, in children with CF in Brazil. Methods: This was a retrospective real-life study in which we reviewed the medical records of pediatric CF patients in whom the eradication protocol was applied between June of 2004 and December of 2012. The three-phase protocol was guided by positive cultures for P. aeruginosa in airway secretions, and the treatment consisted of inhaled colistimethate and oral ciprofloxacin. Success rates were assessed after each phase, as well as cumulatively. Results: During the study period, 47 episodes of P. aeruginosa colonization, in 29 patients, were eligible for eradication. Among the 29 patients, the median age was 2.7 years, 17 (59%) were male, and 19 (65%) had at least one F508del allele. All 29 patients completed the first phase of the protocol, whereas only 12 and 6 completed the second and third phases, respectively. Success rates for eradication in the three treatment phases were 58.6% (95% CI: 40.7-74.5), 50.0% (95% CI: 25.4-74.6), and 66.7% (95% CI: 30.0-90.3), respectively. The cumulative success rate was 93.1% (95% CI: 78.0-98.1). Treatment failure in all three phases occurred in only 2 patients. Conclusions: In this sample of patients, the multistep eradication protocol was effective and had a high success rate.

RESUMO Objetivo: Embora várias estratégias de erradicação de Pseudomonas aeruginosa tenham sido propostas para pacientes com fibrose cística (FC), apenas algumas usaram um tratamento em fases e incluíram crianças na primeira colonização por esse patógeno. O objetivo deste estudo foi descrever a eficácia de um protocolo de erradicação em três fases em crianças com FC a partir do primeiro isolamento de P. aeruginosa no Brasil. Métodos: Estudo retrospectivo de vida real que avaliou prontuários de pacientes pediátricos com FC submetidos ao protocolo de erradicação entre junho de 2004 e dezembro de 2012. O protocolo em três fases foi orientado pela cultura positiva para P. aeruginosa de secreções das vias aéreas, utilizando-se colistimetato inalatório e ciprofloxacina oral no tratamento. As taxas de sucesso após cada fase e a de sucesso acumulado foram avaliadas. Resultados: Durante o período do estudo, 47 episódios de colonização por P. aeruginosa, em 29 pacientes, foram elegíveis para erradicação. Todos os 29 pacientes foram submetidos à primeira fase do protocolo (mediana de idade de 2,7 anos, 17 pacientes (59%) do sexo masculino e 19 (65%) com pelo menos um alelo F508del), sendo que 12 e 6 pacientes foram submetidos a segunda e terceira fases, respectivamente. As taxas de sucesso de erradicação nas três fases de tratamento foram de 58,6% (IC95%: 40,7-74,5), 50,0% (IC95%: 25,4-74,6) e 66,7% (IC95%: 30,0-90,3), respectivamente. A taxa de sucesso acumulado foi de 93,1% (IC95%: 78,0-98,1). Apenas 2 pacientes apresentaram falha do tratamento de erradicação. Conclusões: O primeiro isolamento de P. aeruginosa ocorreu em crianças de baixa idade. O protocolo de erradicação em fases foi efetivo com alta taxa de sucesso.

Prognostic Factors of Central Venous Catheter-related Bloodstream Infections / 中国医学科学院学报

Objective To explore the prognostic factors of central venous catheter-related bloodstream infection(CR-BSI)and provide reference for clinical practice. Methods The clinical data of 346 CR-BSI patients from February 2014 to July 2019 were retrospectively reviewed,and the prognostic factors were analyzed. Results Of the 346 CR-BSI patients,62 died,yielding a case-fatality rate of 17.92%.Univariate analysis showed that 18 factors including age(